1. Field of the Invention
The present invention relates to a laser processing apparatus, a processed data generating method, and a computer program, and particularly relates to improving a method for a user to specify a processing position on an article to be processed when generating processed data for controlling laser processing by the laser processing apparatus.
2. Description of the Related Art
FIG. 20 is a view showing a schematic configuration of a conventional laser processing apparatus 101. The laser processing apparatus 101 is configured by a processed data generating device 1 for generating processed data based on a user operation, and a laser marker 2 for irradiating a work W with a laser light beam L. The laser marker 2 is further configured by a marker head 21 for scanning the laser light beam L on the work W, which is an article to be processed, and a marker controller 22 for performing operation control of the marker head 21 based on the processed data from the processed data generating device 1.
When generating the processed data using the processed data generating device 1, the user needs to designate the processing position on the work W to be irradiated by the laser light beam L as a scanning angle of the laser light beam L by the marker head 21. However, an aim of the user is to perform laser processing on a designated portion on the work W, and it is not easy to accurately specify the scanning angle of the marker head 21 corresponding to this designated portion.
Thus, in a conventional processing apparatus, a task of actually performing the laser processing of the work W, visually checking the processing result, and fine tuning the processing position is repeated. That is, the processing position is specified by trial and error, and thus a working efficiency in creating the processed data is not satisfactory.
An apparatus for irradiating the work W with a visible light beam is known as a laser processing apparatus free of such problems. FIG. 21 is a view showing one example of an improved laser processing apparatus of the conventional art, and shows a configuration of the laser marker 2. The laser light beam generated by a laser oscillation part 211 passes through a beam expander 212, a condenser part 213, a half mirror 214, and a scanning part 215 in order, and then the work W is irradiated with the laser light beam. The scanning angle of the laser light beam L is controlled by the scanning part 215. The visible light beam generated by a light source 217 passes through the half mirror 214 and merges to a light path of the laser light beam, and thereafter, passes through the scanning part 215 and the work W is irradiated with the visible light beam, exactly the same as the laser light beam.
In this laser processing apparatus, a correspondence relationship between an actual position on the work W and the scanning angle of the marker head 21 can be easily specified by irradiating the work W with the visible light beam using the light path of the laser light beam. That is, a spot of the visible light beam is coincided with the designated portion on the work W to be performed with laser processing, and the scanning angle of the marker head 21 at this point is acquired.
In the laser processing apparatus using the visible light beam, the working efficiency in creating the processed data is greatly improved compared to the apparatus in which trial and error needs to be performed. However, the task of coinciding the visible light spot on the designated portion on the work W by changing the scanning angle while visually checking the visible light spot on the work W needs to be performed, and further improvement in the working efficiency is desired. Furthermore, an error by spot diameter and an error by visual checking are inevitable, and thus enhancement in accuracy of the processing position is limited.
Consideration is thus made in taking a picture of the work W with a camera, and specifying the processing position using a photographed image. For instance, if the processing position can be specified on the photographed image, the specific portion on the work W to be performed with laser processing can be directly specified, whereby usability is assumed to be high. However, in the photographed image output from the camera, a distortion is relatively small at a middle of the scanning region of the laser light beam but unignorable distortion occurs at a peripheral part due to a light path difference and an aberration from an optical system and the like. For instance, FIG. 22 shows a photographed image of the middle of the scanning region, and the distortion is relatively small. FIG. 23 is a photographed image of the peripheral part of the scanning region, and a large distortion is found. Furthermore, a difference in the distortion is also found within the photographed image, and the peripheral part of the photographed image has greater distortion compared to the middle even in the photographed image of the middle of the scanning region. Thus, even if the position is specified on the photographed image, the scanning angle corresponding to the relevant position cannot be accurately specified.
Arranging a camera for taking the picture of the work W in the laser processing apparatus has already been proposed (e.g., Japanese Unexamined Patent Publication No. 1-162591 and Japanese Unexamined Patent Publication No. 6-79479). The laser processing apparatus described in Japanese Unexamined Patent Publication No. 1-162591 includes a camera using the path of the laser beam, where a reference light beam is photographed instead of the work W using the camera, and a correction amount of a beam scanner is obtained from a shift amount of a reference position on the photographed image and a position of the reference light beam on the photographed image. That is, the camera is used to compensate the error of the beam scanner, and is not provided to obtain the scanning angle for laser processing the specific portion on the work W desired by the user.
The laser processing apparatus described in Japanese Unexamined Patent Publication No. 6-79479 photographs the work W with the camera, obtains a shift and a tilt from a normal position of the work W based on the photographed image, and adjusts the scanning angle of the laser light beam given in advance. That is, the scanning angle of the laser light beam of when the work W is arranged at the normal position is known, and the scanning angle is automatically fine tuned according to the positional shift of the work on a premise of the known scanning angle. Therefore, the scanning angle corresponding to the specific portion on the work W to which the user desires to perform laser processing is not obtained.